This invention relates to fire extinguishing sprinklers and, more particularly, to new and improved sprinkler arrangements having a compact structure and adapted to respond quickly to elevated temperature conditions indicative of a fire.
Sprinkler systems are widely used for automatic fire protection in residential, commercial and public buildings. Heretofore, many sprinklers have been made with a frame structure incorporating a temperature responsive element located within the frame structure. In order to expose the temperature responsive element to ambient conditions such sprinklers must be mounted so that the entire frame structure including a deflector affixed at its outer end projects downwardly from the ceiling, providing an unattractive appearance. Some conventional sprinklers have a slidable valve and deflector arrangement which is normally retained in a retracted condition by a complex captive locking mechanism that, upon activation, moves with the valve from the retracted close position to an open position. Typical sprinklers of this type are disclosed in U.S. Pat. Nos. 4,491,182, 5,036,923, and 5,094,298.
In other types of quick response sprinklers, such as shown in U.S. Pat. Nos. 4,766,961, 4,785,888 and 6,152,236, the locking mechanism is ejected from the sprinkler when the deflector is moved from the closed position to the open position. Most of the prior art sprinklers of that type include a deflector supported from pins which are slidably supported in lateral extensions of the sprinkler body so that they are normally disposed in the region surrounding the portion of the body containing the passage for water. Such arrangements not only enlarge the size of the sprinkler but also require complex slidable supporting structures for the deflector. U.S. Pat. No. 6,152,236 discloses a sprinkler having a temperature responsive element having the same diameter as the deflector so as to conceal the deflector.
In many sprinklers, a glass bulb is provided as a thermally responsive device to activate the sprinkler at elevated temperatures. Such glass bulbs must be adequately exposed to the surrounding atmosphere to assure a fast response to hot gases but, at the same time, must be adequately protected against accidental or malicious breakage. U.S. Pat. Nos. 5,944,113 and 5,967,237 disclose sprinklers having a glass bulb temperature responsive element which is enclosed in a cage projecting from the outer end of the sprinkler.
Accordingly, it is an object of the present invention to provide a quick response adjustable automatic sprinkler which overcomes disadvantages to the prior art.
Another object of the invention is to provide a quick response sprinkler having a simple and compact configuration.
A further object of the invention is to provide an enclosure for a glass bulb-type temperature sensitive element for a sprinkler which protects the bulb while assuring access to the bulb by high temperature gases.
In accordance with one aspect of the invention a quick response sprinkler arrangement includes a sprinkler body having an axial passage and a deflector supported on a central post which is slidably guided parallel to the axis of the sprinkler passage by a tripod member supported at the outlet end of the passage and having a central opening in which the post is slidable. A tapered neck at the inner end of the post supports a spring washer which engages a shoulder in the passage of the sprinkler body to seal the passage as long as the post and the deflector are retained in an inward position by a locking arrangement. In one form of locking arrangement a plurality of balls are retained by a locking disc so that they engage a peripheral groove in an inner surface of a portion of the sprinkler body, the locking disc being held in position by a thermally responsive element, such as a fusible plug or a glass bulb.
In one embodiment, a plug of fusible material in a tubular housing supports the locking disc in position and heat is transmitted to the fusible material by a heat collecting structure attached to the tubular housing including a thin metal cup member which opens in the direction facing away from the sprinkler passage and a thin metal dish member open inwardly toward the sprinkler passage and having inclined sides with radially projecting cut outs. In another embodiment the thermally responsive element is a glass bulb which is mounted in a cage having a plurality of longitudinal openings which extend parallel to the sprinkler axis and have concave sides shaped to direct gases inwardly from the periphery of the cage toward the bulb mounted in the cage. In a further embodiment the sprinkler arrangement includes a locking disc covering the sprinkler deflector and having a diametrical channel in its outer surface along with lever members received in the channel each having an inner end engaging a peripheral groove in an inner surface of the sprinkler body and an outer end received in a flat horizontally disposed temperature sensitive solder link element so as to retain the locking disc in locking position until they are released by fusing of the solder in the temperature sensitive element. The locking disc also has a peripheral bevel to direct hot gases toward the upper surface of the temperature sensitive level.